Human endometrial cells cultured in a type I collagen gel.

OBJECTIVE: To elaborate in vitro conditions that enable epithelial and stromal cells of human endometrium to grow within a gel of collagen. STUDY DESIGN: Primary cultures of epithelial cells derived from human endometrial biopsies were dissociated and mixed with a collagen solution, and the gel was allowed to form at physiologic pH. Control cultures were grown in plastic dishes. DNA replication was assessed by 3H-thymidine incorporation, morphology by histology and cell characterization by monoclonal antibodies to cytokeratins. RESULTS: Cells grown on plastic dishes exhibited a typical monolayer arrangement, and replication was increased 1.6-fold by the addition of stromal cell-conditioned medium (50% vol/vol). After a two- to three-week period of culture within the collagen gel in the presence of either stromal cells or stromal cell-conditioned medium, epithelial cells formed circular arrangements of cuboidal to columnar cells with open lumina resembling glands. These glandlike structures were cytokeratin positive as assessed by immunohistochemistry, thereby confirming their epithelial nature. CONCLUSION: The development of differentiated epithelial structures in a three-dimensional gel provides a promising method of studying various biochemical and cellular interactions of eutopic and ectopic endometrium.